Access to Fluorene-Fused Isoquinolones Containing an Axially Chiral Element via Cascade Bi-Annulation Reaction of Indene-Dienes

We report an aromatization-driven organocatalytic cascade bi-annulation of indene-dienes, offering a straightforward route to fluorene-fused isoquinolones containing an axially chiral element. By this strategy, with a chiral organocatalyst, axially chiral pyridyl-substituted derivatives were afforded in moderate to good yields (up to 97% yield, 90:10 er). Alternatively, using DMAP and sodium carbonate as bases, structurally phenyl-substituted fluorene-fused isoquinolones were synthesized in up to 99% yield. This protocol directly constructs two distinct classes of fluorene-fused isoquinolone frameworks.